Geared speed reducer with means for adjusting backlash



' July 29, 1947- w. w. HALBROOK 2,424,564 GEARED SPEED REDUCE-B WITHMEANS FOR ADJUSTING BACKLASH Filed July 16, 1945 2 Sheets-Sheet 1 FIG/1INVENTOR W WHAL BROOK a4 a/ as AT TORNEV July 29, 1947-. w; w. HALBROOKGEARED SPEED-REDUCER WITH MEANS FOR ADJUSTING BAcxLAsH Filed July 16,1945 I 2 she'ewg-sneet 2 Fla-5. J

I I lNl/ENTOR W WHALBROUK a (maid V A T TOR/V5 Y Patented its 29, 1947GEARED SPEED REDUCER WITH MEANS FOR ADJUSTING BACKLASH Warwick W.Halbrook, Morristown, N. J., assignor to Bell Telephone Laboratories,Incorporated, New York, N. Y., a corporation of New York ApplicationJuly 16, 1945, Serial No. 605,274

4 Claims. l-

This invention relates to speed reduction mechanism.

The object of the present invention is the provision of a gear speedreduction mechanism which will be simple in construction, compact andwherein means is provided for accurately adjusting the meshing relationof the diflerent gears relative to each other during the initialassembly of the mechanism and to take up backlash between the gears tocompensate for wear.

In the drawing:

Fig. l is an assembly view showing the speed reduction mechanism of theinvention with the casing in longitudinal section and a number of gearsand supports therefor partly in cross-section;

Fig. 2 is a cross-sectional view taken on line 2--2 of Fig. 1 shown witha pinion mounted on one support in meshing relation witha gear mountedon an adjacent-disposed support;

Fig. 3 is a partial view of the mechanism shown in Fig. 1, shown withthe gear supports modified;

Fig. 4 is a, view of one of the gear supports showing the manner ofkeying such supports in adjusted relation to each other in the casing;

Fig. 5 is a partial'view showing three of the gear supports shown inFigs. 3 and 4 modified;

and

Fig. 6 is aplan view of the adjustable bearing for the driving shaft ofthe gear reduction mechanism.

Referring to the drawing, a cylindrical casing ill shown in Fig. 1 isprovided with an opening for receiving a disc member I I. This discmember is secured to the casing by a plurality of screws l4 extending asshown in Fig. 6 through arcuate slots SL in the disc so as to permit therotating adjustment of the latter for a purpose which will behereinafter described in detail. The disc II is provided with a bearingportion l2 for rotatably supporting a shaft l3 to one end of which issecured a pinion IS. The bearing portion I2 is formed eccentrically tothe portion l of the disc which extends into the opening of the casingso that the turning of this disc is effective to position the pinion ISon shaft l3 in adjusted meshing relation with a gear i1. This gear iskeyed on a, spindle l8, journaled at one end, in a support l9 best seenin Fig. 2'secured as by a pair of screws 20 to a disc-shaped support 2ifitted into the casing ill, while th opposite end of spindle i8 isjournaled in a bushing 22 fitted in an opening 23 in the disc-shapedsupport 2i. Support 2| i held against rotation in the casing I0 by a pin24 fitted in a similarly sized notch in the shoulder portion 24Y formedwith the easing ID as shown in Fig. 1 serving for locating this supportin parallel relation with the wall W of the casing.

A pinion 25 which is preferably formed with the spindle it engages witha gear 26 keyed on one end of a spindle 21 journaled in a pair ofsimilarly shaped bushings 28 fitted in an opening 29 disposed ineccentric relation to the periphery of a disc-shaped support 30 fittedin the casing III for substantially 180 degrees angular movement aseii'ected by a worm 3i engaging the worm gear portion 32 of disc-shapedsupport 30, the worm 3| as best seen in Fig. 2 being journaled in a hole33 drilled in an enlarged portion of casing Ill and its opposite end ina bushing 34 threadedly engaging ascrew-threaded bore in the casing l0.

The spindle 21 which is mounted on support 30 is formed with a pinion 35meshing with a gear 36 keyed to one end of a'spindle 31 journaled at oneend in a support ISA and in a bushing 38 fitted in a bore 39 formed in adisc-shaped support 40 fitted in the casing III for angular movement aseffected by a worm 4l engaging the' worm portion 42 of support 40. i l

The spindle 31 as best seen in Fig. 1 is formed with a pinion 43 meshingwith a gear 44 keyed on one end of a shaft 45. This shaft is journaledin a pair of bushings 46 fitted in an opening 41 disposed out, of centerrelative to the periphery of disc-shaped support 41A fitted in thecasing III for angular movement by the rotation of a worm 48 engagingthe worm portion 49 of discshaped support 41A for adjusting the meshingengagement of gear 44 with pinion 43 on discshaped support 40. Thedisc-shaped supports 2|.

30, 40 and 41A are held collectively in parallel relation to each otheragainst the shoulder portion Y of casing ill by a spring ring 50tensioned against the support "A by the screwthreaded engagement of acover 5| with the casing l0.

in the present gear reduction construction, the speed ratio of pinion l6and gear ll is of the order of 4 to 1, that of the pinion 25 and gear26, 4 to 1, that of pinion 35 and gear 36, 4 to 1, and that of pinion 43and gear 44, 4 to 1 giving a speed ratio from driving pinion Hi to thedriven gear 44 and the shaft actuated thereby of the order of 256 turnsto one. The speed ratio however may be decreased and increased to anyvalue desired by decreasing or increasing the numbers of intermeshingpinions and gears as the case may be and/or by changing the tooth ratioof wherein the pin 24 carried by this support engages the notch in theshoulder portion 24Y of the casing and placing the disc support 30 inthe casing with the worm 3| engaging the worm gear portion at the pointY giving a maximum back-v lash between the gear 26 and the pinion 25 andthe placing of the disc supports 40 and 47 in the manner as abovedescribed in connection-with support 2| followed by the tightening ofthecover 5| to the casing while flexing the spring ring 50 in abutment.with cover 5| and thedisc support 41, this ring serving as a barrierfor preventing dust particles entering the casing from the circuhaving aworm gear portion, a worm mounted for rotation in said casing engagingsaid worm portion for rotating said disc-shaped support for adjustablypositioning said gear in meshing relation with the second-mentionedpinion.

2. In a gear reduction mechanism, a cylindrical casing, a stationarydisc-shaped support fitted into said casing, a shaft mounted forrotation on said disc-shaped support, a gear and a pinion carried bysaid shaft, an adjustable disc-shaped suppont fitted in said casing inposition adjacent i to said stationary support, a shaft mounted on saidadjustable disc-shaped support eccentrically relative to the peripherythereof, a gear carried lar opening formed by bushing 45' and cover 5!.

Under this condition, the rotation of worm 3| is effective to rotatethedisc support 30 in the direction indicated by the arrow in Fig. 2,for positioning the gear 25 in accurate meshing relation with pinion 25and this adjustment is repeated for supports 36 and 31 in the mannerdescribed in connection with supporting disc 30.

In actual practice an adjustment as to backlash between the differentgears-has been obtained from the driving shaft l3 to driven shaft 45measuring but a few degrees angle.

In the modification shown in Figs. 3 and 4 the support 501 provided witha pin 5| extending from both sides thereof having one end engaging anotch 52 formed with the cylindrical casing 53 'for'holding the supportagainst turning movement while the opposite end of pin 5| extends intoone of the radial notches N formed in the adjacently disposeddisc-shaped support 55 .de-

- pending upon the adjustment of gear 54 mounted on this supportrelative to pinion 56 mounted on support '50. Similarly a support '57 isprovided with a pin 60 for engaging any one of the notches NI formedwith the support 55 for bolding the support 51 and the gear 58 mountedthereon in adjusted meshing relation with a pinion 59 mounted on support55, the periphery of the supports 50, 55 and 51 having curved surfacesas shown in Figs. 3 and 4 provided to facilitate their insertion andremoval from the casing 53 whenever adjustment of the intermeshing gearsas to backlash is required. r

Fig. 5 discloses a modification of supports 50, 55 and 51 in whichinterengaging saw-toothed portions are provided for preventing rotationof the supports relative to each other in the casing, this constructionbeing particularly well adapted for the die casting of the gear supportsinstead of machining notches in these disc supports.

What is claimed is:

1. In a gear reduction mechanism, a cylindrically-shaped casing, adriving shaft, 2. bearing for said shaft secured to said casing, apinion keyed on said shaft, a disc-shaped support fitted into saidcasing, a spindle mounted for rotation on said support having a gearkeyed on one end thereof, said bearing being adjustable relative to saidgear for positioning said pinion in adjusted meshing relation with saidgear, a pinion on the other end of said spindle, another disc-shapedsupport fitted in said casing, a shaft mounted on said supporteccentrically thereof, a gear keyed on said shaft engaging thesecond-mentioned pinion, the second-mentioned disc-shaped support bysaid shaft, means for holding said adjustable disc-shaped supportagainst movement in said casing following the meshing adjustment of saidgear with said pinion, a driving shaft, a pinion carriedby said shaftengaging the first-mentioned gear, and a bearing for said driving shaftsecured to said casing and adjustable for positioning said driving shaftand the pinion carried thereby in adjusted relation with the first-men.tioned gear. I

. 3. In a gear reduction mechanism, a cylindrical casing, a plurality ofdisc-shaped supports, a number of said supports being movable in saidcasing relative to each other, means carried by the one of said supportsengaging means carried by said casing for holding the last mentionedsupport against movement therein, a pinion and a gear mounted on each ofsaid movable supports the pinions of said supports engaging the gears ofthe other of said supports consecutively to form steps of speedreduction, a driven shaft having a gear meshing with the pinion of thelast speed reduction step, a cover member for said casing, and a, springring tensioned against the support of the last speed reduction by saidcover member for preventing the' entrance of foreign particles from theannular space formed by an opening in said cover member and the bearingfor the shaft of the last speed reduction step.

4. In a gear reduction mechanism, a cylindrical casing, a stationarydisc-shaped support fitted into said casing, a bearing carried by saidsupport, a shaft joumaled in said bearing, a gear and a pinion keyed onsaid shaft, another discshaped support fitted into said casing, a shaftmounted on the last-mentioned support out of center relative to theperiphery of said other discshaped support, a. gear mounted on saidshaft, means for rotating the latter disc shaped support for adjustablypositioning the last-mentioned gear relative to said pinion means forholding the last-mentioned disc-shaped support in said casing relativeto the first-mentioned support following the meshing adjustment of saidear with said pinion, a driving shaft, a pinion keyed on said drivingshaft engaging the first-mentioned gear for driving the first-mentionedshaft.

WARWICK W. HALBROOK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,425,848 Gabrielson Aug. 15,1922 1,720,971 Schweich July 16, 1929 1,746,599 Mahan Feb. 11, 19301,728,279 Ramsey Sept. 17, 1929

